Implantable Sensor Using Photonic Integrated Circuit
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Solution Overview
Problem
Current implantable glucose sensors face stability and reliability issues due to fouling from proteinaceous materials, limiting their use to short-term applications, and existing technologies require invasive methods for substance sampling, which can be painful and costly.
Innovation Solution
A miniaturized, reagent-free, optical sensor system using a photonics integrated circuit for continuous monitoring, allowing for natural substance displacement and reducing bio-fouling, enabling long-term implantation without the need for forced substance sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If surface chemical reaction-based implantable glucose sensors are used, then sensing accuracy is improved, but sensor stability deteriorates due to proteinaceous fouling after a few days
Solution Approach 1:
The patent replaces surface chemical reaction-based sensing with optical spectroscopic sensing. The sensor uses a spectrometer to detect the optical absorption spectrum of glucose at specific wavelengths (2.3 μm region), eliminating the need for surface chemical reactions that are susceptible to protein fouling. This substitution of chemical sensing mechanism with optical sensing enables long-term stable operation.
Solution Approach 2:
The patent introduces an optical intermediary (light at 2.3 μm wavelength) to detect glucose concentrations. Instead of direct contact between the sensor surface and glucose molecules through chemical reactions, the sensor uses optical absorption by glucose molecules in the measurement volume, which can be analyzed without the sensor surface being directly exposed to fouling conditions.
2Difficulty of detecting and measuring
If invasive substance sampling methods are used, then measurement capability is improved, but patient comfort deteriorates due to pain and procedural complexity
Solution Approach 1:
The patent replaces invasive mechanical sampling methods (such as micro-dialysis or ultra-filtration with vacuum sources) with direct optical spectroscopic measurement. The spectrometer measures the optical absorption spectrum of substances in the measurement volume without requiring forced fluid extraction, eliminating painful invasive procedures while maintaining measurement capability.
3Duration of action of stationary object
If spectrometric devices are used for long-term implantation, then sensor durability is improved, but device complexity increases
Solution Approach 1:
The patent integrates the radiation source (tunable VCSEL), spectrometer, and detection electronics into a single implantable device. The spectrometer analyzes the optical absorption spectrum in the 2.3 μm region to simultaneously detect multiple substances (glucose, urea, creatinine, etc.), combining multiple sensing functions into one device to manage complexity while enabling long-term operation.
4Device complexity
If VCSEL with finite tuning range is used, then device integration is improved, but sensing versatility deteriorates due to limited wavelength range
Solution Approach 1:
The patent employs a tunable VCSEL that can dynamically adjust its emission wavelength within the 2.3 μm region. By tuning the laser wavelength, the sensor can detect different substances based on their unique optical absorption spectra (glucose, urea, creatinine, triglyceride, protein, cholesterol, ethanol, ketones, hormones, or lactate), providing versatility through dynamic wavelength adjustment rather than fixed wavelength detection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides accurate, reliable, and comfortable long-term monitoring of glucose and other substances, such as urea, with reduced bio-fouling and mechanical complexity, facilitating continuous, non-invasive measurements and potential integration with closed-loop drug delivery systems.
Implementation Method 1
an integrated radiation source configured for coupling radiation generated by said source into a photonic integrated circuit
Implementation Method 2
an optical demultiplexer and a detection element, said integrated optical waveguide being configured for receiving radiation from said integrated radiation source and to send the radiation to the demultiplexer, said optical de-multiplexer being configured for spectrally processing the radiation
Implementation Method 3
a photonics integrated circuit configured to spectrally process the radiation interacting with the glucose, urea, creatinine, triglyceride, protein, cholesterol, ethanol, ketones, hormones or lactate
Data Source
AI summary
A sensor for sensing a substance such as for example glucose. The sensor is implantable in the body of a living creature. The sensor has a photonic integrated circuit, e.g. silicon-photonics integrated circuit, for spectrally processing radiation interacting with the sample. A continuous monitoring system can also include such a sensor.